Carcinoma orosomucoid-related antigen, a monoclonal antibody thereto, and their uses

Abstract

Disclosed is a glycoprotein, carcinoma orosomucoid-related antigen, (CORA), which has a binding affinity for carcinoembryonic antigen (CEA). This glycoprotein is a marker for carcinoma, and can be characteried by having a molecular weight of about 46,000-50,000 daltons, an isoelectric point of about 3.0-3.5, a carbohydrate content of about 25-35% by weight, reactivity with antisera raised thereto, and substantially no reactivity with antisera raised to nonspecific cross-reacting antigen (NCA) or to CEA. Also disclosed are a hybridoma which produces a monoclonal antibody to CORA, the monoclonal antibody to CORA, and a device, kit, and method for detecting and monitoring carcinoma.

We claim: 
     
       1. A monoclonal antibody specific to carcinoma orosumucoid-related antigen (CORA) glycoprotein, said CORA glycoprotein having a binding affinity for the tumor marker carcinoembryonic antigen (CEA), having a molecular weight of about 46,000-50,000 daltons, an isoelectric point in the range of about 3.0-3.5, a carbohydrate content of about 30% by weight, of which approximately 10.3% is N-acetyl glycosamine and approximately 0.2% is fucose, and having substantially no cross-reactivity with antisera to nonspecific cross-reacting antigen (NCA) or to CEA.   
     
     
       2. The monoclonal antibody of claim 1 wherein said antibody has substantially no cross-reactivity with alpha-1-acid glycoprotein (AGP). 
     
     
       3. The monoclonal antibody of claim 1 wherein said antibody is produced by a hybridoma, said hybridoma being a fusion product of a mouse myeloma cell and a spleen cell from a mouse previously immunized with slow clearing CEA. 
     
     
       4. A hybridoma which produces a monoclonal antibody that is specific to carcinoma orosomucoid-related antigen (CORA) glycoprotein, said antibody having substantially no cross-reactivity with alpha-1-acid (AGP), and   said CORA glycoprotein having a binding affinity for the tumor marker CEA, having a molecular weight of about 46,000-50,000 daltons, an isoelectric point in the range of about 3.0-3.5, a carbohydrate content of about 30% by weight, of which approximately 10.3% is N-acetyl glucosamine and approximately 0.2% is fucose, and having substantially no cross-reactivity with antisera to NCA or to CEA.   
     
     
       5. The hyridoma of claim 4 wherein said hybridoma is a fusion product of a mouse myeloma cell and a spleen cell from a mouse previously immunized with slow clearing CEA. 
     
     
       6. The hybridoma of claim 4 wherein said myeloma cells comprise cells from NS-1 cell line. 
     
     
       7. The hybridoma of claim 4 wherein said mouse had previously been immunized with the CORA glycoprotein. 
     
     
       8. A device for assay or purification purposes, said device comprising: (a) a support; and   (b) at least the Fab portion of said monoclonal antibody of claim 2 bound to said support.   
     
     
       9. A method of detecting a carcinoma cell that synthesizes CEA comprising the steps of: (a) contacting a biological sample with an antibody or the Fab fragment thereof which is specific to carcinoma orosomucoid-related antigen (CORA) glycoprotein but which has substantially no cross-reactivity with alpha-1-acid (AGP),   said CORA glycoprotein having a binding affinity for the tumor marker CEA, having a molecular weight of about 46,000-50,000 daltons, an isoelectric point in the range of about 3.0-3.5, a carbohydrate content of about 30% by weight, of which approximately 10.3% is N-acetyl glucosamine and approximately 0.2% is fucose, having reactivity with a monoclonal antibody raised thereto, and having substantially no cross-reactivity with antisera to NCA or to CEA; and   (b) observing whether said antibody reacts with said sample, a reaction being indicative of the presence of said CEA-synthesizing carcinoma cell.   
     
     
       10. The method of claim 9 wherein said antibody comprises a monoclonal antibody or the Fab fragment thereof which is specific to said CORA glycoprotein. 
     
     
       11. The method of claim 9 wherein said sample comprises biological material selected from a group consisting of whole blood, serum, ascites fluid, and a tissue biopsy, tissue culture, and in vitro histological preparations thereof. 
     
     
       12. A method of detecting and monitoring a patient for colorectal adenocarcinoma comprising the steps of: (a) subjecting a biological sample to a test indicating the presence of a cancer marker carcinoma orosumucoid-related antigen (CORA) glycoprotein,   said CORA glycoprotein having a binding affinity for the tumor marker CEA, having a molecular weight of about 46,000-50,000 daltons, an isoelectric point in the range of about 3.0-3.5, a carbohydrate content of about 30% by weight, of which approximately 10.3% is N-acetyl glucosamine and approximately 0.2% is focuse, having reactivity with a monoclonal antibody raised thereto, and having substantially no cross-reactivity with antisera to NCA or to CEA; and   (b) determining whether the CORA glycoprotein is present, the presence of said CORA glycoprotein being indicative of the presence of colorectal adenocarcinoma.   
     
     
       13. The method of claim 12 wherein said test comprises an immunoassay. 
     
     
       14. A kit for screening a patient for carcinoma, said kit comprising an antibody specific to carcinoma orosomucoid-related antigen (CORA) and further comprising an antibody specific to a carcinoma marker selected from the group consisting of CEA, CA 19.9, NCA and AGP. 
     
     
       15. The kit of claim 14 wherein said kit is useful for screening for colorectal adenocarcinoma.